crypto: asymmetric_keys - select CRYPTO_HASH where needed

Build testing with some core crypto options disabled revealed
a few modules that are missing CRYPTO_HASH:

crypto/asymmetric_keys/x509_public_key.o: In function `x509_get_sig_params':
x509_public_key.c:(.text+0x4c7): undefined reference to `crypto_alloc_shash'
x509_public_key.c:(.text+0x5e5): undefined reference to `crypto_shash_digest'
crypto/asymmetric_keys/pkcs7_verify.o: In function `pkcs7_digest.isra.0':
pkcs7_verify.c:(.text+0xab): undefined reference to `crypto_alloc_shash'
pkcs7_verify.c:(.text+0x1b2): undefined reference to `crypto_shash_digest'
pkcs7_verify.c:(.text+0x3c1): undefined reference to `crypto_shash_update'
pkcs7_verify.c:(.text+0x411): undefined reference to `crypto_shash_finup'

This normally doesn't show up in randconfig tests because there is
a large number of other options that select CRYPTO_HASH.

Signed-off-by: Arnd Bergmann <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

crypto/asymmetric_keys/Kconfig

···
 	select MPILIB
 	select CRYPTO_HASH_INFO
 	select CRYPTO_AKCIPHER
+	select CRYPTO_HASH
 	help
 	  This option provides support for asymmetric public key type handling.
 	  If signature generation and/or verification are to be used,
···
 config PKCS7_MESSAGE_PARSER
 	tristate "PKCS#7 message parser"
 	depends on X509_CERTIFICATE_PARSER
+	select CRYPTO_HASH
 	select ASN1
 	select OID_REGISTRY
 	help
···
 	bool "Support for PE file signature verification"
 	depends on PKCS7_MESSAGE_PARSER=y
 	depends on SYSTEM_DATA_VERIFICATION
+	select CRYPTO_HASH
 	select ASN1
 	select OID_REGISTRY
 	help